«Estrogen, or oestrogen, is the primary femalesex hormone. It is responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three major endogenous estrogens in females that have estrogenic hormonal activity: estrone, estradiol, and estriol. The estranesteroidestradiol is the most potent and prevalent of these.
Estrogens are synthesized in all vertebrates as well as some insects. Their presence in both vertebrates and insects suggests that estrogenic sex hormone have an ancient evolutionary history. The three major naturally occurring forms of estrogen in females are estrone (E1), estradiol (E2), and estriol (E3). Another type of estrogen called estetrol (E4) is produced only during pregnancy. Quantitatively, estrogens circulate at lower levels than androgens in both men and women. While estrogen levels are significantly lower in males compared to females, estrogens nevertheless also have important physiological roles in males.
Like all steroid hormone, estrogens readily diffuse across the cell membrane. Once inside the cell, they bind to and activate estrogen receptors (ERs) which in turn modulate the expression of many genes. Additionally, estrogens bind to and activate rapid-signaling membrane estrogen receptors (mERs), such as GPER (GPR30).
In addition to their role as natural hormone, estrogens are used as medications, for instance in menopausal hormone therapy and hormonal birth control; for information on estrogens as medications, see the estrogen (medication) article.
The four major naturally occurring estrogens in women are estrone (E1), estradiol (E2), estriol (E3), and estetrol (E4). Estradiol is the predominant estrogen during reproductive years both in terms of absolute serum levels as well as in terms of estrogenic activity. During menopause, estrone is the predominant circulating estrogen and during pregnancy estriol is the predominant circulating estrogen in terms of serum levels. Given by subcutaneous injection in mice, estradiol is about 10-fold more potent than estrone and about 100-fold more potent than estriol. Thus, estradiol is the most important estrogen in non-pregnant females who are between the menarche and menopause stages of life. However, during pregnancy this role shifts to estriol, and in postmenopausal women estrone becomes the primary form of estrogen in the body. Another type of estrogen called estetrol (E4) is produced only during pregnancy. All of the different forms of estrogen are synthesized from androgens, specifically testosterone and androstenedione, by the enzymearomatase.
Minor endogenous estrogens, the biosyntheses of which do not involve aromatase, include 27-hydroxycholesterol, dehydroepiandrosterone (DHEA), 7-oxo-DHEA, 7α-hydroxy-DHEA, 16α-hydroxy-DHEA, 7β-hydroxyepiandrosterone, androstenedione (A4), androstenediol (A5), 3α-androstanediol, and 3β-androstanediol. Some estrogen metabolites, such as the catechol estrogens2-hydroxyestradiol, 2-hydroxyestrone, 4-hydroxyestradiol, and 4-hydroxyestrone, as well as 16α-hydroxyestrone, are also estrogens with varying degrees of activity. The biological importance of these minor estrogens is not entirely clear.
The actions of estrogen are mediated by the estrogen receptor (ER), a dimeric nuclear protein that binds to DNA and controls gene expression. Like other steroid hormone, estrogen enters passively into the cell where it binds to and activates the estrogen receptor. The estrogen:ER complex binds to specific DNA sequences called a hormone response element to activate the transcription of target genes (in a study using an estrogen-dependent breast cancer cell line as model, 89 such genes were identified). Since estrogen enters all cell, its actions are dependent on the presence of the ER in the cell. The ER is expressed in specific tissues including the ovary, uterus and breast. The metabolic effects of estrogen in postmenopausal women has been linked to the genetic polymorphism of the ER.
While estrogens are present in both men and women, they are usually present at significantly higher levels in women of reproductive age. They promote the development of female secondary sexual characteristics, such as breasts, and are also involved in the thickening of the endometrium and other aspects of regulating the menstrual cycle. In males, estrogen regulates certain functions of the reproductive system important to the maturation of sperm and may be necessary for a healthy libido.
Estrogens are responsible for the development of female secondary sexual characteristics during puberty, including breast development, widening of the hips, and female fat distribution. Conversely, androgens are responsible for pubic and body hairgrowth, as well as acne and axillary odor.
Estrogen, in conjunction with growth hormone (GH) and its secretory product insulin-like growth factor 1 (IGF-1), is critical in mediating breast development during puberty, as well as breast maturation during pregnancy in preparation of lactation and breastfeeding. Estrogen is primarily and directly responsible for inducing the ductal component of breast development, as well as for causing fat deposition and connective tissue growth. It is also indirectly involved in the lobuloalveolar component, by increasing progesterone receptor expression in the breasts and by inducing the secretion of prolactin. Allowed for by estrogen, progesterone and prolactin work together to complete lobuloalveolar development during pregnancy.
Androgens such as testosterone powerfully oppose estrogen action in the breasts, such as by reducing estrogen receptor expression in them.
Estrogens are responsible for maturation and maintenance of the vagina and uterus, and are also involved in ovarian function, such as maturation of ovarian follicles. In addition, estrogens play an important role in regulation of gonadotropinsecretion. For these reasons, estrogens are required for female fertility.» (wikipedia)
Do something with Estrogen
Lists what BioMindmap can do with its medical objects for demo purposes.
- See 16 Biolinks that connect Estrogen with other objects
- Group Biolinks by type — promoters and inhibitors separately
- Summarize how other objects relate to Estrogen
- There are 11 Evidences supporting 16 Estrogen Biolinks
Guide for Good Sources list of respected domains.
The ValidityScore showsthe quality of evidences, with max 9.9.
- Estrogen Mindmap — near connections
- Mindmap with ValidityScore 5.0 — near connections
- Mindmap of Estrogen. and Subnodes: .
- Find Path to another object.
- Build Custom Map
- Instream into nodes that connect into Estrogen.
- Outstream from nodes that go out from Estrogen.
- Promoters of Estrogen
- Add biolink i.e. «X increases Estrogen». Intuitively easy.
- Power-start: watch the Intro Video and Guide in Help Center
- Users improve Reputation by getting experienced and validated.
- Ask Telegram Bot to get quick Summary on any object.